1. Field of the Invention
The present invention is directed to the field of light sensing and responsive control systems and more specifically to the area of light collectors for use in an automatic headlamp switching system for an automotive vehicle.
2. Description of the Prior Art U.S. Pat. Nos. 4,376,909 and 3,775,639 illustrate respective systems for automatically turning on automotive headlamps in response to a drop in ambient brightness and for automatically switching energized headlamps between high and low beam headlamps in response to oncoming vehicle lights. In each of the aforementioned patents, a light sensitive element is described as being mounted to directly receive the particular light for which the system is to respond.
In a typical implementation of an automatic headlamp-on system, an ambient light sensor module is mounted onto the dashboard of a vehicle so as to receive ambient light entering the windshield. The ambient light sensor module normally includes an exposed photocell along with its own preamplifier in order to provide a corresponding electrical output signal at a high enough level to be conducted to a remotely located control circuit. An associated wiring harness is necessary to interconnect the sensor module to the control circuit and normally one or more removable connectors are included at either end of the harness in the event subsequent repair service necessitates removal of the sensor module.
In a typical installation of the automatic dimming feature, wherein energized headlamps are switched from their high beam to the low beam illumination in response to oncoming vehicle headlamps, an automatic dimmer module is mounted beneath the windshield of a vehicle at the base of a rearview mirror mount. The module contains a lens which has a relatively low angle of vertical acceptance and is directed towards the front of the vehicle. A photocell and preamplifier are included within the automatic dimmer module; and an appropriate wiring harness with connectors provides interconnection of the sensor preamplifier to its associated control circuit.
In each of the described prior art devices, the fabrication of separate light sensor modules as well as the fabrication of wiring harnesses and installation contribute significant cost penalties to the systems and increase the potential for failure and subsequent service.